Assessing psychopathy in the UK: concerns about cross-cultural generalisability

BACKGROUND: The diagnosis of psychopathy is important for violence risk assessment. AIMS: To investigate whether the syndromal structure of psychopathy, as measured by the Psychopathy Checklist-Revised (PCL-R), is the same in the UK and North America, and whether this measure yields scores that are equivalent in these two regions. METHOD: Confirmatory factor analytic and item response theory methods were applied to large samples of PCL-R ratings. RESULTS: The syndromal structure of psychopathy was invariant across cultures, three distinct factors underpinning the superordinate syndrome of psychopathy. However, PCL-R scores were not equivalent across cultures: the same level of psychopathy was associated with lower PCL-R scores in the UK. Items that reflected affective symptoms had the highest cross-cultural stability. CONCLUSIONS: Scores on the PCL-R obtained in the UK are not directly comparable with those obtained in North America. Care must be exercised when the PCL-R is used to make important clinical decisions in the UK.